Is there a decent, generic, CORS proxy script for PHP that Esri's developers would recommend to use with the esri.config.defaults.io.proxyUrl parameter? I'm not a PHP programmer but that is what we use, so if I could get something working our network security folks could vet it. I've seen plenty in use, but because it's server-side, I can't see them, even if they may be freely available somewhere.
